Plastic shotshell and method

ABSTRACT

A shotshell including a plastic tube and a one-piece plastic basewad-overlay disposed in the tube, the basewad-overlay having a boss on the rear face thereof and the tube having a radially inwardly turned rear edge portion extending toward the boss, with a portion of the tube extending radially out be captured within a flange formed on a metallic head element of the shotshell and then continuing under the basewad to mate with the boss portion.

I United States Patent 35654108 [72] Inventors Ronald A. Gulley [56]References Cited Jenning UNITED STATES PATENTS 3,424,089 1/1969Humpherson 102/43 3,442,214 5/1969 Huskins 102/42 Appl' M FOREIGNPATENTS [22] Filed June 26, 1968 [45'] Patented Feb. 23,1971 1,193,3243/1958 France 102/95 [73] Assignee Olin Mathieson Chemical CorporationPrimary Examiner koben F Stab] Attorneys-Donald R. Motsko, H. SamuelKieser, William W.

Jones, Richard S. Strickler, Robert H. Bachman and Thomas P. ODayABSTRACT: A shotshell including a plastic tube and a one- [54] PLAS TICSHOTHEIYL AND METHOD piece plastic basewad-overlay disposed in the tube,the 4 Clams 5 Drawmg basewad-overlay having a boss on the rear facethereof and [52] U.S. Cl 102/43, the tube having a radially inwardlyturned rear edge portion 102/44 extending toward the boss, with aportion of the tube extend- [51] Int. Cl F92b 5/30 ing radially out becaptured within a flange formed on a metal- [50] Field of Search102/42,42 lic head element of the shotshell and then continuing under(C), 73, 44 the basewad to mate with the boss portion.

PATENTEDFEBwsn 3. 565008 INVENTORS. RONALD/4. GULLEY ROBE/PT J KLEINVERNONCMOEHLMAN BY MMMQrM.

ATTORNEY [[6 4 FIG '5 PLASTIC SHOTSIIELL AND METHOD This inventionrelates to a shotshell having a plastic tube, a plastic one-piecebasewad-overlay and a metallic head element, which shotshell permitssuperior reloadability and exhibits excellent gas-sealing properties,acceptable head pull characteristics, and resistance to deterioratingeffects of hot combustion gases.

In the ammunition industry, substantial efforts have been directedtoward the development of a shotshell having a plastic tube to replacethe conventional paper tube due to the fact that plastic shotshell tubespermit superior quality and quality control, provide for lowerproduction costs, and allow standardization of manufacturing techniques.While numerous shotshells having plastic tubes are contained in theprior art, such prior art plastic shotshells have been found to be, forthe most part, commercially nonfeasible due to performance which hasproven inferior to the conventional paper shotshell.

One area wherein the prior art plastic shotshells have been found to beparticularly substandard is the reloadability thereof. The prior artplastic shotshells have been formed with conventional paper or fibrousbasewads and separate paper or fibrous overlay wads, which wads aredeleteriously affected by hot combustion gases and flame-produced whenthe shotshell is fired. Such wads are burned when the shotshell is firedand therefore must be frequently replaced when reloading in order toprovide a safe and reliable reloaded shell. Replacement of the wads isexpensive and time consuming, and often cannot be accomplished without acomplete refabrication of the entire shell.

In order to overcome the above-noted damaging effects upon the basewadand overlay wad caused by hot combustion gases and flame, the prior artdiscloses a plastic shotshell having a composite basewad composed of asawdust or other fibrous core with a comparatively thin plastic overlayconnected thereto, as shown in US. Pat. No. 3,157,121 to BenjaminDaubenspeck et al. This type of prior art plastic shot shell has beenfound to possess undesirable characteristics relating to performancewhen the shell is fired. The force which acts to retain the basewad inthe shell is the press fit of the basewad in the plastic tubing which isin turn held in place by the metal head. The obturation of thethin-skirted overlay portion of the basewad to the tube wall also aidsin this respect. The opposing force, or head pull, which tends to pullthe basewad out of the shell is caused by a vacuum which develops behindthe moving shot charge as the latter leaves the shell and proceedsthrough the barrel of the gun. To properly resist this force, the headmust be firmly connected to each of the other components of the shell.When the shotshell is fired, forces are developed which tend to propelthe basewad and/or the overlay wad into the barrel of the shotgun. Thehead of the shotshell is the only element which tends to retain thebasewad and overlay wad in the shell tube. The head element is sizedonto the basewad, overlay wad, and tube to firmly connect the componentstogether, In order to achieve a satisfactory connection, considerableforce is applied to the exterior of the head during the headingoperation. The composite basewad of the US. Pat. No. 3,157,121 toDaubenspeck et al. has shown undesirable weakness when exposed to thesizing forces, which weakness has been attributed to the fibrous core ofthis basewad. Similar undesirable weakness has been noted when heading aplastic tube shell having a paper or other compacted fibrous basewad.

Still another disadvantage of the prior art composite basewads used inplastic shotshells is their unsuitability for comparatively cold weathershooting. It has been found that the plastic coating, as well as thesawdust inner core, on the composite basewad of the prior art is subjectto cracking when fired in colder temperatures, such as below about F.

This invention provides a plastic shotshell which exhibits superiorreloadability, excellent gas-sealing properties, acceptable resistanceto head pull, and resistance to the deleterious effects of hotcombustion gases and flame. The shotshell of this invention includes aunitary basewad'overlay preferably formed from a solid body ofhigh-density polyethylene plastic. The basewad includes an integralfeathered skirt portion operative to obturate the combustion gasesgenerated when the shell is fired. The basewad-overlay includes acentrally located longitudinal passage for receiving a primer or batterycup, and further includes a boss formed on the rear face of thebasewadcverlay. The basewad-overlay is press fitted into a plastic tube,the latter of which has a rearward edge which is turned inwardly andcurled back upon itself so as to underlie the rear face of thebasewad-overlay and extend toward the boss. The shotshell furtherincludes a metallic head which is fitted onto the exterior of the tubein the area of the basewadoverlay. The head is sized onto the tube andflanged in posi tion so that a portion of the tube adjacent to theinwardly turned edge thereof is squeezed radially outwardly into thehead flange to be captured thereby. When the shell is headed, theinwardly turned edge of the tube is also squeezed against thebasewad-overlay and retained between the head and the basewad-overlay.Since the basewad-overlay is preferably formed from a solid body ofhigh-density polyethylene plastic, it is able to endure, withoutfailure, the forces directed thereagainst when the head is sized andflanged onto the tube. The shell has been consistently fired attemperatures as low as -20 F, without cracking or rupture of thebasewad-overlay.

It is, therefore, an object of this invention to provide a shotshellhaving a plastic tube and a plastic basewad-overlay, which shotshellexhibits superior reloadability.

It is a further object of this invention to provide a shotshell of thecharacter described which is resistant to the deteriorative effects ofhot gases and flame.

It is yet another object of this invention to provide a shotshell of thecharacter described which exhibits acceptable resistance to head pull.

It is still another object of this invention to provide a shotshell ofthe character described which displays excellent obturation ofcombustion gases.

Other objects, features, and advantages of this invention will becomeapparent to one skilled in the art upon examination of the followingdetailed description, when read in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a cross-sectional elevation of a portion of a shotshell formedin accordance with this invention;

FIG. 2 is a cross-sectional elevation of the rearward portion of theshotshell of FIG. 1 showing the shotshell before the head has been sizedand flanged on the tube;

FIG. 3 is an exploded view ofthe various elements shown in FIG. 2;

FIG. 4 is a perspective view of the basewad-overlay with sections cutaway to more clearly show the internal details thereof; and

FIG. 5 is a side elevation, partially in section showing the assembly ofFIG. 2 as the head is sized and flanged on the tube, and showing thesqueezing of the tube into the head flange to be captured thereby.

Referring now to FIG. 1, a preferred embodiment of a portion of ashotshell formed in accordance with this invention is shown. Theshotshell, denoted generally by the numeral 2, includes a plastic tube4, preferably formed from oriented highdensity polyethylene fabricatedin a conventional manner. By high density," it is contemplated that thepolyethylene have a density in the range of, for example, about.940-.96O gm/cm.*. The lower or rearward edge portion of the tube 4 isturned radially inwardly as at 6 with the terminal portion thereof beingturned back upon itself, as at 8. A unitary basewad-overlay 10 having atapered gas obturating skirt 12 is disposed in the tube 4. A boss 14 isformed on the rear or lower face of the basewad-overlay 10 and an axialpassage 16 is disposed in the basewad-overlay 10 to receive a primer cup18. A propellant charge 20 is disposed in the basewad-overlay 10 withwad means 22 overlaying the propellant charge 20. The wad 22 shown asbeing preferred for use in the shotshell of this invention is of thetype disclosed in U.S. Pat. No.

3,285,174; however, it is understood that other wads may be 1866 inplace thereof without departing from the spirit of this invention. Acharge of shot 24 is disposed in the tube 4 above the wad 22 in aconventional manner. A metallic head element 26 is mounted on therearward end of the shell 2, the head 26 including a basal flange 28 inwhich a portion 30 of the tube 4 is captured.

Referring now to FIG. 2, an assembly stage of the shell 2 is shown,wherein the basewad-overlay 10 has been inserted into the tube 4, andthe tube 4 and basewad-overlay 10 have been inserted into the head 26,the latter of which includes a partially formed flange 28. FIG. 3 is anexploded view of the assembly of FIG. 2 which more clearly shows theconfiguration of the rearward end of the basewad-overlay 10, and therearward edge portion of the tube 4. It is noted that the boss 14 formedon the rearward face of the basewad-overlay 10 is inwardly offset fromthe sidewall of the basewad-overlay to define a shoulder 15. It isfurther noted that the rearward edge portion of the tube 4 is turnedradially inwardly at 6 with the terminal portion 8 thereof curled backupon itself. Upon assembly, the inwardly turned edge portion 6 of thetube 4 is sandwiched between the rear face of the basewad-overlay 10 andthe bottom wall ofthe head 26.

FIG. 4 is a perspective view of the basewad-overlay l having a portionthereof cut away for purposes of clarity. The basewad-overlay is aunitary member formed, preferably, from a solid body of high-densitypolyethylene. The upper, or forward end of the basewad-overlay includesa tapered annular thin-walled skirt 12 which obturates by action ofcombustion gases, flaring outwardly against the wall of the tube 4 whenthe shell is fired. The middle portion of the basewadoverlay 10 includesa comparatively thick-walled propellant cut 32 having a frustoconicalinner wall 34. An aperture 16 is axially disposed in thebasewad-overlay, to receive a primer cup (see FIG. 1). The boss 14,formed on the rear face of the basewad-overlay, is preferably outwardlyspaced from the rim of the aperture 16 and inwardly spaced from theoutside wall of the basewad-overlay.

FIG. 5 shows the heading operation in which the head 26 is sized ontothe shell. The partially formed shell of FIG. 2 is disposed on asupporting member 36 and moved into a female die 38. The head 26 is thensized and flanged by moving the die 38 and the supporting member 36together in the direction of the arrows 40 so as to cause the die 38 topress the head 26 onto the tube 4 and basewad-overlay 10. As the head 26is compressed and flanged, frictional contact between the head 26 andthe tube 4 causes the rearward end of the latter to be squeezed radiallyoutwardly, as at 30, into the head flange 28. The tube 4 is thus firmlyretained at the portion or flange 30 by the head flange 28, and at theradially inwardly turned flange 6 by being sandwiched between the head26 and the rear face of the basewad-overlay 10. Furthermore, theprovision of a solid plastic basewad-overlay permits the use of higherheading pressures to be used in the fabrication of the shell.

It is thus apparent that a shell formed in accordance with thisinvention displays superior reloadability due to the fact that the shellis more resistant to the deleterious effects of firing. The solidplastic basewad-overlay provides resistance to hot combustion gases, andflame, stability at low-firing temperatures, and strength not found inthe prior art basewad structures. The positive double interlock betweenthe tube and the head flange on one hand, and the tube, the head, andthe basewad-overlay on the other hand provides superior resistance tohead pull not found in the prior art plastic shotshells.

Although reference has been made to a particular embodiment of thepresent invention, various modifications will readily suggest themselvesto those skilled in the art and reference should be made to the appendedclaims to determine the scope of the invention.

We claim:

I. A shotshell comprising:

a. plastic tube means; A b. a unitary basewad-overlay member containedwithin said tube means, said member having a cylindrical sidewall and aprojecting boss formed on a rear face thereof, said boss forming ashoulder inwardly spaced from said sidewall of said member;

c. a metallic head element mounted on said tube means,

said head element having a basal flange; and

d. said tube means including a rearward end comprising a first radiallyinwardly extending portion having a terminal portion curled back uponitself to form a double thickness said radially inwardly extendingportion and said curled back portion being squeezed between said headelement and said basewad-overlay member and against said shoulder, and asecond radially outwardly extending portion of said tube means beingcaptured by said head flange.

2. The shotshell of claim 1, wherein said basewad-overlay member iscomposed of a solid piece of polyethylene having a density of about .940to .960 grams per cubic centimeter.

3. A shotshell comprising:

a. a high-density polyethylene tube having an inwardly turned rearwardedge, said inwardly turned rearward edge having a thickness which issubstantially greater than the thickness of the remainder of said tube;

b. a unitary, high-density, solid polyethylene basewad-overlay memberdisposed in said tube, said member including a projecting shoulderclosely adjacent to said inwardly turned edge of said tube;

c. a metallic head element sized onto said tube about saidbasewad-overlay member, said head element having a flange; and

d. said inwardly turned edge of said tube being trapped between andsqueezed by said basewad-overlay member and said head against saidshoulder, and said head flange being operative to capture a portion ofsaid tube.

4. A shotshell comprising:

a. a plastic tube means having a constricted rearward opening formed byan inwardly extending part on said tube, said part having a thicknesswhich is approximately twice the thickness of the remainder of saidtube;

b. basewad-overlay means disposed in said tube means, saidbasewad-overlay means comprising a boss projecting through saidconstricted rearward opening and snugly gripped by said thicker tubepart; and

c. head means sized on said tube, said head means being operative tofasten said tube means to said basewad-overlay and squeeze said thickertube part against said boss, and said head means including a flangeoperative to capture a portion of said tube means.

1. A shotshell comprising: a. plastic tube means; b. a unitarybasewad-overlay member contained within said tube means, said memberhaving a cylindrical sidewall and a projecting boss formed on a rearface thereof, said boss forming a shoulder inwardly spaced from saidsidewall of said member; c. a metallic head element mounted on said tubemeans, said head element having a basal flange; and d. said tube meansincluding a rearward end comprising a first radially inwardly extendingportion having a terminal portion curled back upon itself to form adouble thickness said radially inwardly extending portion and saidcurled back portion being squeezed between said head element and saidbasewad-overlay member and against said shoulder, and a second radiallyoutwardly extending portion of said tube means being captured by saidhead flange.
 2. The shotshell of claim 1, wherein said basewad-overlaymember is composed of a solid piece of polyethylene having a density ofabout .940 to .960 grams per cubic centimeter.
 3. A shotshellcomprising: a. a high-density polyethylene tube having an inwardlyturned rearward edge, said inwardly turned rearward edge having athickness which is substantially greater than the thickness of theremainder of said tube; b. a unitary, high-density, solid polyethylenebasewad-overlay member disposed in said tube, said member including aprojecting shoulder closely adjacent to said inwardly turned edge ofsaid tube; c. a metallic head element sized onto said tube about saidbasewad-overlay member, said head element having a flange; and d. saidinwardly turned edge of said tube being trapped between and squeezed bysaid basewad-overlay member and said head against said shoulder, andsaid head flange being operative to capture a portion of said tube.
 4. Ashotshell comprising: a. a plastic tube means having a constrictedrearward opening formed by an inwardly extending part on said tube, saidpart having a thickness which is approximately twice the thickness ofthe remainder of said tube; b. basewad-overlay means disposed in saidtube means, said basewad-overlay means comprising a boss projectingthrough said constricted rearward opening and snugly gripped by saidthicker tube part; and c. head means sized on said tube, said heaD meansbeing operative to fasten said tube means to said basewad-overlay andsqueeze said thicker tube part against said boss, and said head meansincluding a flange operative to capture a portion of said tube means.